World's Largest Canyon System Discovered Beneath Antarctic Ice Sheet

Antarctica wasn’t always a vast, frozen desert. 100 million years ago, this huge land mass was covered in lush, dense rainforests, and it contained many landscape features that nowadays have been concealed by blankets of ice. For decades, scientists have been trying to image the bedrock hidden underneath the surface, and as part of this endeavor, a team of researchers may have discovered a crevasse that is over twice the size of the Grand Canyon in the U.S. Their remarkable discovery has been described in the journal Geology.

East Antarctica has two fairly underexplored regions: Princess Elizabeth Land (PEL) and Recovery Basin. Known by scientists as “Poles of Ignorance,” they are both the target of intense study, particularly in regards to what may lie beneath them. After all, understanding the bedrock of Antarctica is vital if researchers are to understand how the icy continent will behave as the world continues to warm. Ice moves across the land according to the landscape it’s sitting on, so mapping any subglacial geological features is a necessity for climatologists.

In the same way, the surface shape of the ice is influenced by what it is resting on, so by looking at the surface, we can infer what may be hiding underneath it. With this in mind, an international team of scientists used a complex combination of satellites, including radar, to image the ice sheets on PEL; a few elongated linear features, previously unspotted, immediately got their attention.

These surface lineations appear to trace out the shape of a vast canyon system over 1,000 kilometers (620 miles) long, and in places up to one kilometer (0.62 miles) deep. This would make it the largest canyon system in the entire world. Although further geophysical surveys are required to confirm that the bedrock beneath these features actually take the form of a canyon, the researchers are fairly confident of their claims.

“Where we have good bed data coverage [elsewhere in Antarctica], we see these type of surface features above them, so we have confidence that the new surface features are from a subglacial structure,” Prof. Martin Siegert, a coauthor of the paper and researcher at Imperial College London, told IFLScience. “Indeed, knowledge from other areas inform us that they should be valleys/canyons.”

The researchers’ understanding of subglacial water drainage, along with the discovery of this canyon and its incredible dimensions, has led them to hypothesize the existence of a vast, connected lake also concealed beneath the ice. This lake could be up to 1,250 square kilometers (483 square miles) in area.

Both the lake and the canyon theories are supported by initial results from new radar scanning, which is able to see through the ice layers. In order to definitively confirm the existence of both of these phenomenal features, additional radar surveys across thousands of kilometers of Antarctic ice sheets are taking place between British, American and Chinese scientists.

When completed, they will have a truly comprehensive view of the bedrock – a project that has essentially been over five decades in the making. “The region in question is the last part of Antarctica to be explored in this way, and so the canyon will likely be the last major geomorphological feature left to be discovered,” Siegert noted.

“Indeed it is likely to be the last major geomorphological feature on the land surface of our planet to be discovered.”